Cooling structure of motor

Abstract

To reduce cost while securing supply of cooling oil to a lower part of a coil end part.SOLUTION: A cooling structure of a motor including a stator having an annular stator core and a stator coil wound around the stator core and having coil end portions protruding from both sides of the stator core in an axial direction includes a plurality of oil passages formed at intervals in a circumferential direction of the stator core and each penetrating the stator core in the axial direction, and a guide portion provided on one end side of the stator core in the axial direction and guiding cooling oil flowing through some of the plurality of oil passages to the coil end portions. The guide portion is provided so as to extend along the circumferential direction only in at least a part of a range of 90 degrees on both sides from a lowermost end in the circumferential direction on the outer peripheral side of the coil end portion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a cooling structure for a motor. [Background technology]

[0002] Conventionally, a cooling structure for a motor has been proposed, which includes a stator having a stator core and a stator coil, a housing to which the stator is fixed, and a pump that discharges cooling oil (see, for example, Patent Document 1). In this motor cooling structure, a cooling oil passage is provided in the housing to guide the cooling oil discharged from the pump. Also, a coil end cover is provided to cover the coil end portion, which is a portion of the stator coil that is axially offset from the stator core. Furthermore, a gap is formed between the coil end portion and the coil end portion over substantially the entire surface of the coil end cover facing the coil end portion, through which cooling oil from the cooling oil passage is guided. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-14857 Summary of the Invention [Problem to be solved by the invention]

[0004] In the cooling structure of the motor described above, the coil end cover covers almost the entire surface facing the coil end portion, but even without the coil end cover, cooling oil from the cooling oil passages can be applied to the coil end portion by gravity in the upper circumferential portion of the coil end portion (for example, within 90 degrees on both sides from the uppermost end in the circumferential direction). In contrast, if the coil end cover were to be eliminated, it would be difficult to apply sufficient cooling oil from the cooling oil passages to the lower (vertically lower) portion of the coil end portion. Given these factors, it is necessary to reduce costs while ensuring that cooling oil can be applied to the lower portion of the coil end portion.

[0005] The motor cooling structure of the present disclosure has a primary object to reduce costs while ensuring that cooling oil is supplied to the lower portion of the coil end portion. [Means for solving the problem]

[0006] The motor cooling structure of the present disclosure employs the following measures to achieve the above-mentioned main object.

[0007] The motor cooling structure of the present disclosure includes: A cooling structure for a motor including a stator having an annular stator core and a stator coil wound around the stator core and having coil end portions protruding from both sides in an axial direction of the stator core, a plurality of oil passages formed at intervals in the circumferential direction of the stator core and each penetrating through the stator core in the axial direction; a guide portion provided at one end of the stator core in the axial direction and configured to guide the cooling oil that has flowed through some of the plurality of oil passages to the coil end portion; Equipped with The guide portion is provided so as to extend along the circumferential direction on the outer circumferential side of the coil end portion and only in at least a portion within a range of 90 degrees on both sides from the lowest end in the circumferential direction. The gist of this is as follows.

[0008] The motor cooling structure disclosed herein includes a guide portion disposed at one end of the stator core in the axial direction and configured to guide cooling oil circumferentially through some of the oil passages to the coil end portion. The guide portion extends circumferentially radially outward of the coil end portion and at least partially within a 90-degree range from the lowest end of the coil end portion on both sides of the circumferential direction. This allows the cooling oil circulating through the oil passages to be supplied to the lower portion of the coil end portion by the guide portion. Furthermore, the cooling oil circulating through the oil passages falls by gravity to the upper portion of the coil end portion, where no guide portion is provided. By providing the guide portion only at least partially within a 90-degree range from the lowest end of the stator core (coil end portion) on both sides of the circumferential direction, material for the guide portion can be reduced, thereby reducing costs compared to a configuration in which the guide portion is provided around the entire circumference of the stator core. This allows for cost reduction while ensuring the supply of cooling oil to the lower portion of the coil end portion. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic configuration diagram of a motor unit 10 according to an embodiment of the present disclosure. [Figure 2] FIG. 10 is a schematic diagram of a motor unit 110 according to a modified example. [Figure 3] 10 is a schematic diagram of a modified example of a motor unit 210, 310. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] A mode (embodiment) for carrying out the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic diagram of a motor unit 10 according to an embodiment of the present disclosure. FIG. 1(A) shows a cross-sectional view of the motor unit 10. FIG. 1(B) shows a front view of the motor unit 10. FIG. 1(A) corresponds to a cross-sectional view of the motor unit 10 taken along line AA in FIG. 1(B). FIG. 1(B) corresponds to an external view of the motor unit 10 as viewed from the right side in FIG. 1(A). Note that the permanent magnets 18 of the rotor 14 and the motor case 40 are omitted from FIG. 1(B). Also, for ease of viewing, the coil end portion 26 and the guide portion 30 are hatched in FIG. 1(B). The orientation (vertical direction) of the arrangement of the motor unit 10 is as shown in FIGS. 1(A) and 1(B).

[0011] The motor unit 10 of this embodiment is mounted on an electric vehicle, a hybrid vehicle, a fuel cell vehicle, etc., and includes a motor 12 configured as a synchronous generator motor, a guide portion 30 used to guide cooling oil that cools the motor 12, and a motor case 40 that houses the motor 12 and the guide portion 30. The motor 12 includes a rotor 14 fixed to a rotor shaft RS, and a stator 20 that houses the rotor 14 in its center.

[0012] The rotor 14 has an annular rotor core 16 and permanent magnets 18 embedded in the rotor core 16 at intervals in the circumferential direction. The rotor core 16 is fixed to a rotor shaft RS that is inserted inside the rotor core 16. The stator 20 has a stator core 22 having an annular portion and a plurality of teeth that protrude inward at intervals in the circumferential direction from the inner circumference of the annular portion, and a stator coil 24 that is wound around the plurality of teeth of the stator core 22. The stator coil 24 has coil end portions 25, 26 that protrude from both sides in the axial direction of the stator core 22. A plurality of oil passages 23 (e.g., the same number as the teeth) are formed on the outer circumferential side (radially outward) of the stator coil 24 of the stator core 22, spaced apart in the circumferential direction and each penetrating the stator core 22 in the axial direction. In this embodiment, cooling oil is supplied from an oil pump to the coil end portions 25 via oil passages and guide portions (neither of which are shown), and is also supplied to the plurality of oil passages 23 from the coil end portion 25 side in the axial direction of the stator core 22 (see the thick arrow on the left side of the stator core 22 in FIG. 1(A)). This guide portion is made of resin, for example, and is formed in a shape that covers the entire circumference of the coil end 25. By supplying the cooling oil to the coil end portions 25, the coil end portions 25 can be cooled. Furthermore, by circulating the cooling oil through the plurality of oil passages 23, the stator core 22 and the portions of the stator coils 24 that do not protrude from the stator core 22 in the axial direction can be cooled.

[0013] The guide portion 30 is provided on the coil end portion 26 side of the stator core 22 in the axial direction and stores cooling oil that has flowed through some of the multiple oil passages 23 and guides it to the coil end portion 26. The guide portion 30 is made of, for example, resin. The guide portion 30 may be fixed to the end surface of the stator core 22 on the coil end portion 26 side in the axial direction, or may be fixed to the motor case 40 so as to abut against this end surface. The guide portion 30 is provided to extend circumferentially from the lowest end (vertical lower end) of the stator core 22 in the circumferential direction within a range of 90 degrees on both sides in the circumferential direction (the range of the lower half). The guide portion 30 has a first wall portion 31 that is outer peripherally of the multiple oil passages 23 of the stator core 22 and extends along the axial and circumferential directions of the stator core 22, and a second wall portion 32 that extends inward from the axial tip end (the end opposite the stator core 22) of the first wall portion 31. The axial length of the first wall portion 31 is longer than the axial length of the coil end portion 26. Therefore, the guide portion 30 protrudes axially outward (away from the stator core 22) beyond the coil end portion 26. The inner diameter of the second wall portion 32 may be smaller than the outer diameter of the coil end portion 26, or may be approximately the same as the outer diameter of the coil end portion 26.

[0014] With this guide portion 30, the cooling oil that flows through the oil passages 23, among the multiple oil passages 23, that are provided in approximately the lower half of the stator core 22, is stored in the guide portion 30, or flows inward along the second wall portion 32 of the guide portion 30 and is supplied to the coil end portion 26 (see the thick arrow to the right of the stator core 22 and below the rotor shaft RS in FIG. 1A). The cooling oil also flows out of the guide portion 30 from the gap between the coil end portion 26 and the guide portion 30 (second wall portion 32). Furthermore, the cooling oil that flows through the oil passages 23, among the multiple oil passages 23, that are provided in approximately the upper half of the stator core 22, falls by gravity and is supplied to the coil end portion 26 (see the thick arrow to the right of the stator core 22 and above the rotor shaft RS in FIG. 1A). Therefore, if the guide portions 30 are provided in the lower half of the stator core 22 in the circumferential direction, the coil end portions 26 can be cooled to some extent along the entire circumference without being provided along the entire circumference. Also, by providing the guide portions 30 only in the lower half of the stator core 22 in the circumferential direction, it is possible to reduce the material for the guide portions 30 and reduce costs compared to providing the guide portions 30 along the entire circumference. As a result, in the motor unit 10, costs can be reduced while ensuring that cooling oil is supplied to the lower portions of the coil end portions 26.

[0015] The motor unit 10 (cooling structure of the motor 12) of the embodiment described above includes a guide portion 30 that is provided on the coil end portions 26 side of the stator core 22 in the axial direction and that guides cooling oil that has flowed through some of the oil passages 23 to the coil end portions 26. The guide portion 30 is provided on the outer peripheral side (radially outer side) of the coil end portions 26 and extends circumferentially only within a range of 90 degrees on both sides from the lowest end of the stator core 22 in the circumferential direction. This allows the cooling oil that has flowed through the oil passages 23 to be supplied to the lower portions of the coil end portions 26 by the guide portion 30. Furthermore, the cooling oil that has flowed through the oil passages 23 falls by gravity and is supplied to the upper portions of the coil end portions 26, such as portions where the guide portion 30 is not provided. By providing the guide portions 30 only within a range of 90 degrees on either side of the lowest end of the stator core 22 (coil end portions 26) in the circumferential direction, it is possible to reduce the material for the guide portions 30 and thereby reduce costs compared to providing the guide portions 30 around the entire circumference of the stator core 22. Therefore, in the motor unit 10, it is possible to reduce costs while ensuring that cooling oil is supplied to the lower portions of the coil end portions 26.

[0016] In the above-described embodiment, the guide portion 30 of the motor unit 10 protrudes axially outward (away from the stator core 22) beyond the coil end portion 26, but this is not limited thereto. FIG. 2 is a schematic diagram of a modified motor unit 110. FIGS. 2A and 2B correspond to FIGS. 1A and 1B. The motor unit 110 of FIG. 2 uses a guide portion 130 instead of the guide portion 30 of the motor unit 10. The guide portion 130 has a first wall portion 131 and a second wall portion 132, which differ from the first wall portion 31 and the second wall portion 32 of the guide portion 30 in the following respects. The axial length of the first wall portion 131 is shorter than the axial length of the coil end portion 26. Therefore, the guide portion 130 does not protrude axially outward beyond the coil end portion 26. The inner periphery of the second wall portion 132 abuts against the outer periphery of the coil end portion 26, and a plurality of notches 133 are formed on the inner periphery side of the second wall portion 132 at intervals in the circumferential direction.

[0017] With this guide portion 130, the cooling oil that has flowed through some of the oil passages 23 (oil passages 23 provided in the lower half of the stator core 22) is stored in the guide portion 130 or supplied to the coil end portion 26. When supplied to the coil end portion 26, the oil may flow, for example, along the second wall portion 132 to the inner circumferential side and be supplied to the portion of the coil end portion 26 on the stator core 22 side (such as the gap with the end face of the stator core 22), or may flow in the axial direction via the cutout 133 and be supplied to the outer periphery of the coil end portion 26. This provides the same effect as the motor unit 10 (the cooling structure of the motor 12).

[0018] In the above-described embodiment, the guide portions 30, 130 of the motor units 10, 110 are provided so as to extend circumferentially within a range of 90 degrees on either side (the lower half) from the lowest end (vertical lower end) of the stator core 22. However, this is not limited thereto, and the guide portions 30, 130 may be formed only in at least a portion of the range of 90 degrees on either side from the lowest end of the stator core 22 in the circumferential direction. FIG. 3 is a schematic configuration diagram of modified motor units 210, 310. FIG. 3(A) shows the motor unit 210, and FIG. 3(B) shows the motor unit 310. As shown in the motor unit 210 in FIG. 3(A), the guide portions 230 may be provided so as to extend circumferentially within a range of approximately 45 degrees on either side from the lowest end of the stator core 22 in the circumferential direction. As shown in motor unit 310 in FIG. 3(B), guide portion 330 may be provided to extend circumferentially within a range of about 15 to 20 degrees on both sides from the lowest end of stator core 22 in the circumferential direction.

[0019] In the above-described embodiment, the guide portions 30, 130, 230, 330 of the motor units 10, 110, 210, 310 are provided so as to extend along the circumferential direction within ranges of the same angle on both sides from the lowest end in the circumferential direction of the stator core 22. However, the guide portions may be provided so as to extend along the circumferential direction within ranges of different angles on both sides from the lowest end in the circumferential direction of the stator core 22. For example, the guide portions may be provided so as to extend along the circumferential direction within a range of a first angle (e.g., several degrees) on one side from the lowest end in the circumferential direction of the stator core 22 and a second angle (e.g., approximately 45 degrees) on the other side.

[0020] Although not specifically described in the above embodiment, the cooling oil may be supplied with a certain amount of pressure to the plurality of oil passages 23 from the coil end portions 25 side in the axial direction of the stator core 22. This makes it easier to increase the amount of cooling oil that flows through some of the oil passages 23 and flows to the inner periphery along the second wall portion 32 of the guide 30 to be supplied to the coil end portions 26.

[0021] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section will be described below. In the embodiment, the stator core 22 corresponds to the "stator core," the coil end portion 26 corresponds to the "coil end portion," the stator coil 24 corresponds to the "stator coil," the stator 20 corresponds to the "stator," the motor 12 corresponds to the "motor," the multiple oil passages 23 correspond to the "multiple oil passages," and the guide portion 30 corresponds to the "guide portion."

[0022] The correspondence between the main elements of the embodiments and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the embodiments are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the embodiments are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0023] The above describes the forms for implementing the present disclosure using embodiments, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0024] The present disclosure is applicable to industries such as the manufacturing industry of motor cooling structures. [Explanation of symbols]

[0025] 10,110,210,310 Motor unit, 12 Motor, 14 Rotor, 16 Rotor core, 18 Permanent magnet, 20 Stator, 22 Stator core, 23 Oil passage, 24 Stator coil, 25 Coil end portion, 26 Coil end portion, 30,130,230,330 Guide portion, 31,131 First wall portion, 32,132 Second wall portion, 40 Motor case.

Claims

[Claim 1] A cooling structure for a motor including a stator having an annular stator core and a stator coil wound around the stator core and having coil end portions protruding from both sides in an axial direction of the stator core, a plurality of oil passages formed at intervals in the circumferential direction of the stator core and each penetrating through the stator core in the axial direction; a guide portion provided at one end of the stator core in the axial direction and configured to guide the cooling oil that has flowed through some of the plurality of oil passages to the coil end portion; Equipped with The guide portion is provided so as to extend along the circumferential direction on the outer circumferential side of the coil end portion and only in at least a portion within a range of 90 degrees on both sides from a lowest end in the circumferential direction. Motor cooling structure.

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